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rf704_amplitudefit.C
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1 /// \file
2 /// \ingroup tutorial_roofit
3 /// \notebook
4 /// Special pdf's: using a pdf defined by a sum of real-valued amplitude components
5 ///
6 /// \macro_image
7 /// \macro_output
8 /// \macro_code
9 ///
10 /// \date July 2008
11 /// \author Wouter Verkerke
12 
13 #include "RooRealVar.h"
14 #include "RooDataSet.h"
15 #include "RooGaussian.h"
16 #include "RooConstVar.h"
17 #include "RooTruthModel.h"
18 #include "RooFormulaVar.h"
19 #include "RooRealSumPdf.h"
20 #include "RooPolyVar.h"
21 #include "RooProduct.h"
22 #include "TH1.h"
23 #include "TCanvas.h"
24 #include "TAxis.h"
25 #include "RooPlot.h"
26 using namespace RooFit;
27 
28 void rf704_amplitudefit()
29 {
30  // S e t u p 2 D a m p l i t u d e f u n c t i o n s
31  // -------------------------------------------------------
32 
33  // Observables
34  RooRealVar t("t", "time", -1., 15.);
35  RooRealVar cosa("cosa", "cos(alpha)", -1., 1.);
36 
37  // Use RooTruthModel to obtain compiled implementation of sinh/cosh modulated decay functions
38  RooRealVar tau("tau", "#tau", 1.5);
39  RooRealVar deltaGamma("deltaGamma", "deltaGamma", 0.3);
40  RooTruthModel truthModel("tm", "tm", t);
41  RooFormulaVar coshGBasis("coshGBasis", "exp(-@0/ @1)*cosh(@0*@2/2)", RooArgList(t, tau, deltaGamma));
42  RooFormulaVar sinhGBasis("sinhGBasis", "exp(-@0/ @1)*sinh(@0*@2/2)", RooArgList(t, tau, deltaGamma));
43  RooAbsReal *coshGConv = truthModel.convolution(&coshGBasis, &t);
44  RooAbsReal *sinhGConv = truthModel.convolution(&sinhGBasis, &t);
45 
46  // Construct polynomial amplitudes in cos(a)
47  RooPolyVar poly1("poly1", "poly1", cosa, RooArgList(RooConst(0.5), RooConst(0.2), RooConst(0.2)), 0);
48  RooPolyVar poly2("poly2", "poly2", cosa, RooArgList(RooConst(1), RooConst(-0.2), RooConst(3)), 0);
49 
50  // Construct 2D amplitude as uncorrelated product of amp(t)*amp(cosa)
51  RooProduct ampl1("ampl1", "amplitude 1", RooArgSet(poly1, *coshGConv));
52  RooProduct ampl2("ampl2", "amplitude 2", RooArgSet(poly2, *sinhGConv));
53 
54  // C o n s t r u c t a m p l i t u d e s u m p d f
55  // -----------------------------------------------------
56 
57  // Amplitude strengths
58  RooRealVar f1("f1", "f1", 1, 0, 2);
59  RooRealVar f2("f2", "f2", 0.5, 0, 2);
60 
61  // Construct pdf
62  RooRealSumPdf pdf("pdf", "pdf", RooArgList(ampl1, ampl2), RooArgList(f1, f2));
63 
64  // Generate some toy data from pdf
65  RooDataSet *data = pdf.generate(RooArgSet(t, cosa), 10000);
66 
67  // Fit pdf to toy data with only amplitude strength floating
68  pdf.fitTo(*data);
69 
70  // P l o t a m p l i t u d e s u m p d f
71  // -------------------------------------------
72 
73  // Make 2D plots of amplitudes
74  TH1 *hh_cos = ampl1.createHistogram("hh_cos", t, Binning(50), YVar(cosa, Binning(50)));
75  TH1 *hh_sin = ampl2.createHistogram("hh_sin", t, Binning(50), YVar(cosa, Binning(50)));
76  hh_cos->SetLineColor(kBlue);
77  hh_sin->SetLineColor(kRed);
78 
79  // Make projection on t, plot data, pdf and its components
80  // Note component projections may be larger than sum because amplitudes can be negative
81  RooPlot *frame1 = t.frame();
82  data->plotOn(frame1);
83  pdf.plotOn(frame1);
84  pdf.plotOn(frame1, Components(ampl1), LineStyle(kDashed));
85  pdf.plotOn(frame1, Components(ampl2), LineStyle(kDashed), LineColor(kRed));
86 
87  // Make projection on cosa, plot data, pdf and its components
88  // Note that components projection may be larger than sum because amplitudes can be negative
89  RooPlot *frame2 = cosa.frame();
90  data->plotOn(frame2);
91  pdf.plotOn(frame2);
92  pdf.plotOn(frame2, Components(ampl1), LineStyle(kDashed));
93  pdf.plotOn(frame2, Components(ampl2), LineStyle(kDashed), LineColor(kRed));
94 
95  TCanvas *c = new TCanvas("rf704_amplitudefit", "rf704_amplitudefit", 800, 800);
96  c->Divide(2, 2);
97  c->cd(1);
98  gPad->SetLeftMargin(0.15);
99  frame1->GetYaxis()->SetTitleOffset(1.4);
100  frame1->Draw();
101  c->cd(2);
102  gPad->SetLeftMargin(0.15);
103  frame2->GetYaxis()->SetTitleOffset(1.4);
104  frame2->Draw();
105  c->cd(3);
106  gPad->SetLeftMargin(0.20);
107  hh_cos->GetZaxis()->SetTitleOffset(2.3);
108  hh_cos->Draw("surf");
109  c->cd(4);
110  gPad->SetLeftMargin(0.20);
111  hh_sin->GetZaxis()->SetTitleOffset(2.3);
112  hh_sin->Draw("surf");
113 }
RooFormulaVar.h
c
#define c(i)
Definition: RSha256.hxx:101
RooTruthModel.h
RooPlot::Draw
virtual void Draw(Option_t *options=0)
Draw this plot and all of the elements it contains.
Definition: RooPlot.cxx:691
rf704_amplitudefit
Definition: rf704_amplitudefit.py:1
RooArgList
RooArgList is a container object that can hold multiple RooAbsArg objects.
Definition: RooArgList.h:21
RooGaussian.h
RooAbsReal
RooAbsReal is the common abstract base class for objects that represent a real value and implements f...
Definition: RooAbsReal.h:61
TAttLine::SetLineColor
virtual void SetLineColor(Color_t lcolor)
Set the line color.
Definition: TAttLine.h:40
TCanvas.h
RooFit::YVar
RooCmdArg YVar(const RooAbsRealLValue &var, const RooCmdArg &arg=RooCmdArg::none())
Definition: RooGlobalFunc.cxx:246
RooFit::Binning
RooCmdArg Binning(const RooAbsBinning &binning)
Definition: RooGlobalFunc.cxx:83
TH1::GetZaxis
TAxis * GetZaxis()
Definition: TH1.h:322
RooDataSet.h
RooPlot::frame
static RooPlot * frame(const RooAbsRealLValue &var, Double_t xmin, Double_t xmax, Int_t nBins)
Create a new frame for a given variable in x.
Definition: RooPlot.cxx:249
RooPolyVar.h
RooProduct
A RooProduct represents the product of a given set of RooAbsReal objects.
Definition: RooProduct.h:30
RooFormulaVar
A RooFormulaVar is a generic implementation of a real-valued object, which takes a RooArgList of serv...
Definition: RooFormulaVar.h:30
RooFit
The namespace RooFit contains mostly switches that change the behaviour of functions of PDFs (or othe...
Definition: RooCFunction1Binding.h:29
RooAbsData::plotOn
virtual RooPlot * plotOn(RooPlot *frame, const RooCmdArg &arg1=RooCmdArg::none(), const RooCmdArg &arg2=RooCmdArg::none(), const RooCmdArg &arg3=RooCmdArg::none(), const RooCmdArg &arg4=RooCmdArg::none(), const RooCmdArg &arg5=RooCmdArg::none(), const RooCmdArg &arg6=RooCmdArg::none(), const RooCmdArg &arg7=RooCmdArg::none(), const RooCmdArg &arg8=RooCmdArg::none()) const
Definition: RooAbsData.cxx:547
RooPlot.h
RooPlot::GetYaxis
TAxis * GetYaxis() const
Definition: RooPlot.cxx:1258
RooPlot
A RooPlot is a plot frame and a container for graphics objects within that frame.
Definition: RooPlot.h:44
RooRealVar.h
kRed
@ kRed
Definition: Rtypes.h:66
RooPolyVar
Class RooPolyVar is a RooAbsReal implementing a polynomial in terms of a list of RooAbsReal coefficie...
Definition: RooPolyVar.h:28
RooProduct.h
RooConstVar.h
RooFit::LineColor
RooCmdArg LineColor(Color_t color)
Definition: RooGlobalFunc.cxx:57
f1
TF1 * f1
Definition: legend1.C:11
TCanvas
The Canvas class.
Definition: TCanvas.h:23
TAxis.h
TH1
TH1 is the base class of all histogramm classes in ROOT.
Definition: TH1.h:58
kBlue
@ kBlue
Definition: Rtypes.h:66
kDashed
@ kDashed
Definition: TAttLine.h:48
gPad
#define gPad
Definition: TVirtualPad.h:287
RooDataSet
RooDataSet is a container class to hold unbinned data.
Definition: RooDataSet.h:33
RooFit::LineStyle
RooCmdArg LineStyle(Style_t style)
Definition: RooGlobalFunc.cxx:58
TAttAxis::SetTitleOffset
virtual void SetTitleOffset(Float_t offset=1)
Set distance between the axis and the axis title.
Definition: TAttAxis.cxx:293
RooRealSumPdf.h
RooRealVar
RooRealVar represents a variable that can be changed from the outside.
Definition: RooRealVar.h:37
RooFit::Components
RooCmdArg Components(const RooArgSet &compSet)
Definition: RooGlobalFunc.cxx:75
TH1.h
RooRealSumPdf
The class RooRealSumPdf implements a PDF constructed from a sum of functions:
Definition: RooRealSumPdf.h:25
RooArgSet
RooArgSet is a container object that can hold multiple RooAbsArg objects.
Definition: RooArgSet.h:29
RooTruthModel
RooTruthModel is an implementation of RooResolution model that provides a delta-function resolution m...
Definition: RooTruthModel.h:21
TH1::Draw
virtual void Draw(Option_t *option="")
Draw this histogram with options.
Definition: TH1.cxx:3050
RooFit::RooConst
RooConstVar & RooConst(Double_t val)
Definition: RooGlobalFunc.cxx:347